Search results for "Cytochrome"
showing 10 items of 607 documents
Phenotype traits associated with different alleles at the RPS5 locus in Saccharomyces cerevisiae
1992
The RPS5 gene has been characterised through its ability to reduce invertase production by the SUC5 gene. In this paper we show that RPS5 acts by maintaining low levels of SUC5 mRNA. We also show that RPS5 acts on the SUC1 and SUC4 genes but not on SUC2 and SUC3, which are members of the SUC family. RPS5 also shows a pleiotropic effect on the amount of mitochondrial cytochromes.
The catalytic activity of the endoplasmic reticulum-resident protein microsomal epoxide hydrolase towards carcinogens is retained on inversion of its…
1996
Diol epoxides formed by the sequential action of cytochrome P-450 and the microsomal epoxide hydrolase (mEH) in the endoplasmic reticulum (ER) represent an important class of ultimate carcinogenic metabolites of polycyclic aromatic hydrocarbons. The role of the membrane orientation of cytochrome P-450 and mEH relative to each other in this catalytic cascade is not known. Cytochrome P-450 is known to have a type I topology. According to the algorithm of Hartman, Rapoport and Lodish [(1989) Proc. Natl. Acad. Sci. U.S.A. 86, 5786–5790], which allows the prediction of the membrane topology of proteins, mEH should adopt a type II membrane topology. Experimentally, mEH membrane topology has been …
Pharmacogenetic considerations for optimizing tacrolimus dosing in liver and kidney transplant patients
2013
The introduction of tacrolimus in clinical practice has improved patient survival after organ transplant. However, despite the long use of tacrolimus in clinical practice, the best way to use this agent is still a matter of intense debate. The start of the genomic era has generated new research areas, such as pharmacogenetics, which studies the variability of drug response in relation to the genetic factors involved in the processes responsible for the pharmacokinetics and/or the action mechanism of a drug in the body. This variability seems to be correlated with the presence of genetic polymorphisms. Genotyping is an attractive option especially for the initiation of the dosing of tacrolim…
Effect of CYP3A5*3 on kidney transplant recipients treated with tacrolimus: a systematic review and meta-analysis of observational studies
2014
The highly variable pharmacokinetics of tacrolimus can hamper the optimal management of kidney transplant patients. This variability has been attributed to the genetic polymorphism of CYP3A5 6986A>G, but the evidence is not clear. We conducted a meta-analysis of studies evaluating the effect of CYP3A5 polymorphism on kidney transplant recipients with tacrolimus plasma concentration divided by daily dose per body weight (C/D) and clinical outcomes. We searched in MEDLINE and EMBASE. We found evidence suggesting a significantly lower C/D among CYP3A5*1 allele carriers compared with carriers of the CYP3A5*3/*3 genotype at weeks 1 and 2, and months 1, 3, 6 and 12. We demonstrated that the expre…
Guanine 6-O-Methylation Pattern within the Dioxin Responsive Element of theCYP1A1 Enhancer Shows Two Critical Guanines for AhR/ARNT Binding
2006
The core-recognition motif for TCDD-liganded AhR/ARNT complex of the dioxin-responsive element (DRE) contains four guanine residues, three on the antisense (5'-T T / A GCGTG-3') and one on the sense (5'-CACGC A / T A-3') strand. It has been reported that, in methylation-protection and methylation-interference assays, the TCDD-liganded AhR/ARNT contacts all four guanine residues. On the other hand, it is known that some anticancer drugs, and various environmental and workplace chemicals, including strongly human carcinogenic nitrosoamines, lead to the highly miscoding 6-O-methylation of guanine. In the present study, we have investigated whether specific methylation of guanine at the 6-O-pos…
Molecular evidence for the presence of cryptic evolutionary lineages in the freshwater copepod genus Hemidiaptomus G.O. Sars, 1903 (Calanoida, Diapto…
2010
The pattern of morphological and mtDNA cytochrome b diversity of three calanoid copepod species belonging to the diaptomid genus Hemidiaptomus has been investigated with the aim of checking the reliability of the morphological characters currently used for species identification, and the possible presence of cryptic taxa. A sharply different molecular structuring has been observed in the studied species: while Hemidiaptomus amblyodon exhibits a remarkable constancy throughout the European range of its distribution area (maximum inter-populations cytochrome b divergence of 3%), observed distances between presumed conspecific lineages of Hemidiaptomus gurneyi (maximum divergence of 21.5%) and…
Activation of a caspase-3-independent mode of cell death associated with lysosomal destabilization in cultured human retinal pigment epithelial cells…
2008
International audience; Purpose: To characterize the possible cytotoxic effects of oxysterols (7-hydroxycholesterol (7-OH), 25-hydroxycholesterol (25-OH)) in human retinal pigment epithelial cells (ARPE-19) and to detail the relationships between some of these effects. Methods: ARPE-19 cells were treated with 7-OH and 25-OH. Cell viability was measured with the MTT assay. Membrane permeability, mitochondrial potential, and lysosomal integrity were measured by flow cytometry with propidium iodide, DiOC6(3), and acridine orange, respectively. Cell death was characterized by staining with Hoechst 33342, transmission electron microscopy, and analysis of the DNA fragmentation pattern. Caspase ac…
Cytochrome b sequences of ancient cattle and wild ox support phylogenetic complexity in the ancient and modern bovine populations.
2009
Mitochondrial DNA has been the traditional marker for the study of animal domestication, as its high mutation rate allows for the accumulation of molecular diversity within the time frame of domestic history. Additionally, it is exclusively maternally inherited and haplotypes become part of the domestic gene pool via actual capture of a female animal rather than by interbreeding with wild populations. Initial studies of British aurochs identified a haplogroup, designated P, which was found to be highly divergent from all known domestic haplotypes over the most variable portion of the D-loop. Additional analysis of a large and geographically representative sample of aurochs from northern and…
Drug-metabolizing enzyme activities in freshly isolated oval cells and in an established oval cell line from carcinogen-fed rats
1994
The activities of several different phase I and phase II drug-metabolizing enzymes were measured in freshly isolated oval cells from rats fed a choline-deficient/DL-ethionine-supplemented diet for 6 weeks and also in vitro in the established oval cell line OC/CDE 6. No cytochrome P450 was spectrophotometrically measurable in both preparations and two cytochrome P450-dependent monoxygenase activities, aminopyrine N-demethylase and ethoxyresorufin O-deethylase, could not be detected in the oval cells of both sources. However, cytosolic glutathione transferase, microsomal epoxide hydrolase and UDP-glucuronosyltransferase activities were clearly measurable in oval cells. Similar enzyme activiti…
The aryl hydrocarbon receptor-dependent deregulation of cell cycle control induced by polycyclic aromatic hydrocarbons in rat liver epithelial cells
2006
Disruption of cell proliferation control by polycyclic aromatic hydrocarbons (PAHs) may contribute to their carcinogenicity. We investigated role of the aryl hydrocarbon receptor (AhR) in disruption of contact inhibition in rat liver epithelial WB-F344 'stem-like' cells, induced by the weakly mutagenic benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF) and by the strongly mutagenic benzo[a]pyrene (BaP). There were significant differences between the effects of BaA and BbF, and those of the strongly genotoxic BaP. Both BaA and BbF increased percentage of cells entering S-phase and cell numbers, associated with an increased expression of Cyclin A and Cyclin A/cdk2 complex activity. Their eff…